1. Field of the Invention
The present invention relates generally to downhole well tools of the type used in oil and gas wells and, in particular, to a wireline set and tubing retrievable production packer for use to prevent a fluid flow through a wellbore casing.
2. Description of the Prior Art
Prior art retrievable packers have been used in oil and gas completion operations for lowering within wellbores on a wireline, and setting within a casing string to prevent a wellbore fluid from flowing between a tubing string and the casing string. Prior art retrievable packers typically include an elastomeric packing means which is compressed to sealingly engage between a sleeve included within the retrievable packer and the interior of a casing string set within the wellbore.
Prior art retrievable packers have been releasably secured to wireline run setting tools by shear pins. However, in slimhole, and other applications, there may not be enough circumferential space between connecting members for placement of sufficient shear pins to provide adequate support for transferring enough setting force to the retrievable packer to urge it into setting engagement within the wellbore.
Additionally, prior art retrievable packers include slip-gripping mechanisms having a set of slip elements which are wedged outwardly until they grippingly engage between a casing string and a retrievable packer to support the retrievable packer at a downhole depth within the wellbore. These prior art slip-gripping mechanisms have been held in place, grippingly engaging the casing, by a ramped surface pressing beneath the slip elements to wedge them laterally outward towards the casing. A coil spring locates between the upper slips and the setting sleeve. Improvements are desired.